Concrete form



Feb. 25, 1 969 o. c. BURTON 3,429,241

CONCRETE FORM Filed NOV. 28, 1966 Sheet of 5 62 so I 33 =1 62 g f ---33 33 INVENTOR DUANE C. BURTON MM QA/ ATTORNEYS D. C. BURTON CONCRETE FORM Feb. 25, 1969 Sheet 2 Filed Nov. 28, 1966 INVENTOR DUANE C. BURTON ATTORNEYS x A A a Fehzs, 1969 D. C. BURTON CONCRETE FORM Sheet 3 of 5 Filed Nov. 28, 1966 INVENTOR DUANE C. BURTON ATTORNEYS 3,429,241 CONCRETE FORM Duane C. Burton, Boulder, Colo., assignor, by mesne assignments, to The Ankortite Company, Inc., Franklin Park, 11]., a corporation of Delaware Filed Nov. 28, 1966, Ser. No. 597,337 US. Cl. 9417 15 Claims Int. Cl. E01c 11/02, 23/02 ABSTRACT OF THE DISCLOSURE A concrete form used in forming a contraction joint and an elongated member for use in such joint. The concrete form comprises a plurality of aligned stakes each of which has a generally vertically disposed body portion, a top portion and a support means disposed beneath the top portion generally transversely to said body portion, and an elongated relatively rigid sheet material member having means disposed in supporting engagement with at least a portion of the transversely disposed support means of two or more of said stakes. The joint forming member comprises upper and lower longitudinally extending, generally co-planar portions and a longitudinally extending key deformation portion interposed between and connected to the upper and lower portions, said upper planar portion having an upper edge, said member including means formed within the upper planar portion or adjacent said planar portion for engaging a generally horizontally disposed support means of a supporting structure to support said member whereby the upper edge of said member may be disposed along a predetermined grade level.

Cross references to related patents US. patents illustrative of those which are related generally to the concrete form of this invention are Nos. 3,143,783 (class 25118), 3,057,269 (class 94-17), 1,880,- 013 and 1,770,359.

This invention relates to the construction of concrete slabs and more particularly to a concrete form of the type used in forming a key contraction joint between adjacent concrete slabs which may be used for concrete slabs of varying thicknesses and particularly for concrete slabs carrying relatively heavy loads, and for a joint forming member useful in such concrete forms.

Heretofore, many concrete forms of the type used in forming a key contraction joint between adjacent concrete slabs have been proposed, especially for monolithically poured concrete slabs. Many of these forms have had useful application. However, each of these forms has suffered from a number of disadvantages. For example, many of the prior art forms were disadvantageous in that a considerable amount of expense and time was required to install same. Additionally, other prior art forms were disadvantageous due to the fact that they could not be used in concrete slabs subjected to relatively large loads without spalling occurring. Further, many of the prior art concrete forms were disadvantageous since no inexpensive means were available to prevent a joint member used within a concrete form floating upwardly within the mass of concrete following pouring thereof. It has been discovered, however, that each of the foregoing disadvantages may be quickly and easily overcome through the use of a novel concrete form comprising a plurality of aligned stakes each of which has a horizontally disposed support means and an elongated relatively rigid sheet material member having a longitudinally extending key deformation portion connected to a longitudinally extending generally planar portion, said upper planar portion having means formed therein disposed in supporting engagement with at least a nited States Patent 3,429,241 Patented Feb. 25, 1969 portion of the support means of said stakes, said upper portion also having a folded-over portion at the upper edge thereof, said folded-over portion extending downwardly against at least a part of said upper portion.

Accordingly, one of the principal objects of this invention is to provide a new and improved concrete form of the type used in forming a key contraction joint between adjacent concrete slabs.

Another object of this invention is to provide a concrete form which may be used with concrete slabs which are to be subjected to relatively heavy loads.

Another object of this invention is to provide a concrete form which may be easily and quickly installed and which at the same time incorporates means for preventing the joint forming member used therein from floating upwardly under the influence of the pressure existing within the concrete following the pouring thereof.

Another object of this invention is to provide a new and novel joint forming member for forming a key contraction joint between adjacent concrete slabs.

Another object of this invention is to provide an improved concrete form of the type used in forming a key contraction joint between adjacent slabs which, in a preferred embodiment, eliminates the use of an inverted stake pocket disposed adjacent the upper portion of the joint forming member used in such form and disposed in a direction opposite to the key deformation portion of such member.

Another object of this invention is to provide a concrete slab key joint forming member employed in the construction of concrete roadways, floors and airfield runways which may be quickly and easily installed and which has an upper portion which is reinforced by folding over a portion of the material used to form the joint forming member.

Another object of this invention is to provide a concrete form of the type used in forming a key contraction joint between adjacent concrete slabs, said joint comprising a plurality of aligned stakes, each of said stakes having a generally vertically disposed body portion, a top portion and a support means disposed generally transversely to said body portion, at least a portion of each of said support means being disposed along a first predetermined grade level; and an elongated relatively rigid sheet material member having means disposed in supporting engagement for at least a portion of the support means of each of said stakes, said member also having an upper, longitudinally extending, generally planar portion and a lower, longitudinally extending key deformation portion connected to said upper portion, said planar portion being disposed against said stake, said upper portion having a folded-over portion at the upper edge, thereof, said least a part of said upper portion, the upper edge of said folded-over portion being disposed at a second predetermined grade level.

Another object of this invention is to provide a joint forming member for forming a key contraction joint between adjacent concrete slabs, said member comprising upper and lower longitudinally extending, generally coplanar portions and a longitudinally extending key deformation portion interposed between and connected to said upper and lower portions, said upper portion having a folded-over portion extending downwardly against at least a part of said upper portion, said folded-over portions being of less height than said upper planar portion, and means formed within the upper planar portion for engaging a generally horizontally disposed means of a supporting structure to support said member with the upper edge thereof disposed along a predetermined grade level whereby said planar portions of said member are disposed in a generally vertical plane adjacent a generally vertically disposed surface of a supporting structure.

Another object of this invention is to provide a joint forming member having upper and lower longitudinally extending generally co-planar portions and a longitudinally extending key deformation portion interposed between and connected to said upper and lower portions, said upper planar portion including a generally horizontally disposed recess portion, said recessed portion being constructed to receive a generally horizontally disposed support means of a supporting structure, said recess portions being disposed in the same direction as said key deformation portion.

Further objects and advantages of the invention will become apparent from the following description and claims and from the accompanying drawings, wherein:

FIGURE 1 is a vertical section through adjoining concrete slabs of a concrete road showing one embodiment of a concrete form constructed in accordance with the subject invention;

FIGURE 2 is a perspective view of one embodiment of a joint forming member constructed in accordance with the subject invention;

FIGURE 3 is a side elevational view of one embodiment of a stake useful in a concrete form constructed in accordance with the subject invention;

FIGURE 4 is an end elevational view of the stake showin in FIGURE 3;

FIGURE 5 is a plan view of the stake shown in FIG- URE 3;

FIGURE 6 is a cross-sectional view of another embodiment of a concrete form constructed in accordance with the subject invention and of a joint forming member useful therein;

FIGURE 7 is a side elevational view of the stake shown in FIGURE 6;

FIGURE 8 is a perspective view of another embodiment of a concrete form constructed in accordance with the subject invention and of a joint-forming member useful therein;

FIGURE 9 is a partial cross-sectional view taken along line 9-9 of FIGURE 8;

FIGURE 10 is a side elevational view taken of the stake shown in FIGURE 9;

FIGURE 11 is a cross-sectional elevational view of another embodiment of a concrete form constructed in accordance with the subject invention and of a joint forming member useful therein;

FIGURE 12 is a perspective view of the joint forming member shown in FIGURE 11;

FIGURE 13 is a cross-sectional view of the upper part of another embodiment of another concrete form constructed in accordance with the subject invention and of a joint forming member useful therein;

FIGURE 14 is a perspective view, in partial cross-sectional, of the upper part of another concrete form constructed in accordance with the subject invention and of a joint forming member useful therein;

FIGURE 15 is a perspective view of the upper part of another embodiment of a concrete form constructed in accordance with the subject invention and a joint form in g member useful therein;

FIGURE 16 is a plan view of a portion of a crimping tool; and

FIGURE 17 is a perspective view, in partial crosssection, of another embodiment of a concrete form constructed in accordance with this invention and of a joint forming member useful therein.

Referring now to the drawings, in FIGURE 1 is shown a vertical section through adjoining concrete slabs of a concrete road showing the preferred embodiment of a concrete form 20 constructed in accordance with the subject invention. The concrete form 20 is of the type used in forming a key contraction joint between adjacent concrete slabs 22 and 24 and comprises a plurality of aligned stakes 26 (only one of which is shown) and an elongated relatively rigid sheet material member 28, see FIGURE 2.

Each of the stakes 26, see FIGURES 3-5, has a generally vertically disposed body portion 30 and a support means or tab 32 disposed generally transversely to said body portion 30. A portion of each said support means 32 of each of said stakes 26 is disposed along a first predetermined grade level represented in FIGURE 1 by dotted line 34. Each tab 32, as shown in FIGURE 1, is preferably bent upwardly or downwardly to insure further that the member is secured relative to the stakes. The member 28 has means 36, see FIGURE 2, disposed in supporting engagement with at least a portion of the support means 32 of each of said stakes 26. Member 28 also has upper and lower longitudinally extending generally co-planar portions 38 and 40 and a longitudinally extending key deformation portion 42 interposed between and connected to said upper and lower planar portions 38 and 40, said planar portions 38 and 40 being disposed against vertically disposed surface portions of said stakes 26. It will be noted that the corners 43 and 44 of the key deformation portion 42 are arcuately shaped. The purpose for this is to minimize any stress concentrations forming with the edges of the concrete formed adjacent said corners 43 and 44. The upper and lower planar portions 38 and 40 incorporate longitudinally extending corrugations 46 which increase the overall rigidity of member 38. The upper planar portion 38 of member 28 has a folder-over portion 45 depending from the upper edge 47 thereof and extending downwardly against at least a part 48 of said upper planar portion 38. The upper edge 47 of said folded-over portion 45 and said upper planar portion 38 is disposed at a second predetermined grade level represented by the upper surface of concrete slabs 22 and 24 as shown by line 50 in FIGURE 1. The folded-over portion 45 is of less height than the height of upper planar portion 38. Member 28 preferably includes a plurality of groups 52 of apertures 54 longitudinally spaced along the lower planar portion 40 of member 28. The longitudinal spacing of the groups 52 of apertures corresponds to the longitudinal spacing of the means 36.

As shown in FIGURE 1, the concrete form 20 preferably includes a means 56 such as a screw disposed within one of the apertures 33 of the stake 26 and a corresponding aperture 54 formed in the lower planar portion 40 of member 28. The purpose of means or screw 56 disposed in this manner is to insure further against vertical movement of member 28 relative to the stake 26. The key deformation portion 42 of member 28 is preferably provided with a number of suitably spaced apertures 58 which are adapted to receive slidably a metal dowel or rod 59. A block of wood 60 is also shown secured to the lower portion of the stake 26 by any suitable means such as nails 61. The use of a block of wood 60, such as a piece of a 2 x 4", is usually limited to those cases where the subgrade 62 is more loosely completed than is the normal case. Understandably, the block 60 is attached to the stake 26 before same is driven into the subgrade 62.

In FIGURE 6 is shovm another embodiment of a concrete form 63 constructed in accordance with the subject invention. The concrete form 63 comprises a plurality of aligned stakes 64 (only one of which is shown in FIGURE 6) and an elongated relatively rigid sheet material member 66. Each of the stakes 64 has first and second support means 68 and 70, see also FIGURE 7, disposed generally transversely to the remaining portion of said stake. The first support means 68 has a portion thereof disposed along a first predetermined grade level as represented by dotted line 72 while the second support means 70 has a portion thereof disposed along a third predetermined grade level as represented by dotted line 74. Second support means is preferably bent toward the adjacent portion of the stake 64 to secure further the member 66 to said stake 64. Member 66 is substantially similar to member 28 shown in FIGURE 2 except that member 66 does not have the groups 52 of apertures 54 formed in the lower planar portion thereof as is the case with member 28 or the corrugations 46. Further, the lower part of the upper planar portion of member 66 is disposed initially out of contact with the stake 64.

In FIGURES 8-10 is shown another concrete form 78 constructed in accordance with this invention and a stake useful therein. The concrete form 78 comprises a plurality of aligned stakes 80, see FIGURE 8, and an elongated relatively rigid sheet material member 82. Each of the stakes 80 is similar in construction to stake 26 shown in FIGURES 3 and 4, except that the support means 84, see FIGURES 9 and 10, which is transversely disposed with respect to the remaining portion of the stake 80 is preferably formed to intersect the remaining portion of stake 80 at an acute angle rather than being disposed at right angles to the remaining portion of stake 80. The purpose for this is to facilitate the installation of the member 82 upon the support means 84 of stake 80 as will be later more fully described. Each stake 80 also includes a plurality of apertures 86 which serve the same purpose as apertures 33 in stake 26 as shown in FIGURES 3 and 4. A separate means such as a screw 88 is disposed within one of the apertures 86 and extends through a corresponding aperture (not shown) formed in the lower planar portion of member 82.

The two members 82 shown in FIGURE 8 are similar in construction to member 28 as shown in FIGURE 2 except with respect to the formation of the upper planar portion 90. The upper planar portion 90 includes a generally horizontally disposed recess portion 92 in which is disposed the support means 84 of the stake 80. The recess portion 92 is disposed in the same direction as the key deformation portion 94. The recess portion 92 is, in cross-section, circumscribed by a generally arcuately formed wall surface 96 thereby greatly minimizing the formation of longitudinally extending sharp corners on the surface of the concrete slab to be formed adjacent the outer surface of the recess portion. This feature is quite important in minimizing any undue stress concentrations which otherwise occur along such sharp cornered edges thereby minimizing the tendency of the concrete slab to chip or spall at such points. The upper planar portion 90 has a folded-over portion 98 extending downwardly against at least a part 100 of said upper planar portion 90. It will be noted that the folded-over portion 98 is of less height than the height of the upper planar portion 90. Further, a part 102 of the folded-over portion 98 extends transversely downwardly across the opening leading into the recess portion 92. As will now be readily obvious in light of the foregoing, the lower planar portion 104 has a plurality of groups of apertures (not specifically shown) longitudinally spaced along said lower planar portion 104 much in the same manner as is the case with the groups 52 of apertures formed in the lower planar portion 40 of member 28 as shown in FIGURE 2.

In FIGURES 11 and 12 is shown another concrete form 106 constructed in accordance with the subject invention and the joint forming member used therein. The concrete form 106 comprises a plurality of aligned stakes 108 (only one of which is shown in FIGURE 11) and an elongated relatively rigid sheet material member 110. Each stake 108 is generally similar in construction to the stake 64 shown in FIGURE 7. More specifically, stake 108 has a first support means 112 and a second support means 114. The member 110 has upper and lower, longitudinally extending, generally co-planar portions '116 and 118 and a longitudinally extending key deformation portion 120 interposed between and connected to said upper and lower planar portions. The upper planar portion 116 has a generally horizontally disposed recess portion 122 formed therein and extending in the same direction as the key deformation portion 120. The upper planar portion 116 has a folded-over portion 124 extending downwardly from the upper edge 125 of the upper planar portion 116 and against at least a part 126 of the upper 6 planar portion 116. It will be noted in FIGURE 11 that the first support means 112 is disposed within said recess portion 122. Additionally, the second support means 114 has been urged toward the remaining portion of the stake 108 until said second support means 114 securely clamps the lower planar portion 118 of member against the remaining portion of the stake 108 thereby preventing vertical movement of the member'110 relative to the stake 108. Although a sharp cornered edge is formed in the adjacent concrete slab at the intersection of the horizontally disposed wall 127 partially surrounding said recess portion 122 and part 126 of upper planar portion 116, it will be noted that the mass of concrete formed above said wall 112 is of rather substantial thickness and, accordingly, the tendency for such formed concrete to spall or chip away under relatively heavy loads is greatly minimized thereby greatly adding to the beneficial results obtained from the use thereof.

In FIGURE 13 is shown a modified version of a recess portion 128 formed in the upper planar portion 130 of a joint forming member constructed in accordance with the subject invention. It will be noted that the recess portion 128 is generally horizontally disposed and extends in the same direction as the key deformation portion of said joint forming member. The recess portion 128 is circumscribed by wall surfaces which, in cross section, describe an R configuration lying on its side. As such, the opening leading into the recess portion 128 is wider than the narrowest dimension, taken in a vertical plane, of the R configuration. This configuration facilitates in the mounting of the joint forming member upon the horizontally disposed support means 132 of the stake 133 since the opposed converging wall surfaces 134 and 1 35 of the R configuration guide the support means 122 into the recess portion 128. The distance separating the narrowest part of the R configuration is made equal to or slightly less than the depth of the support means 132. Thus, when the support means 132 is fully disposed within the recess portion 128, the recess portion 128 and the support means 132 cooperate to prevent vertical movement of the joint forming member relative to the stake 133.

In FIGURE 14 is shown a modified version of the upper portion of a concrete form 136 constructed in accordance with the subject invention. The concrete form 136 comprises a plurality of aligned stakes 138 (only one of which is shown in FIGURE 14) and an elongated relatively rigid sheet material member 140. The concrete form 138 is generally similar to the concrete form shown in FIGURE 1 except that the member 140 does not have a folded-over portion depending downwardly from the upper edge 142 thereof, and the top 144 of the stake 138 is positioned on line with the upper edge 142 of the member 140. However, it will also be understood that the top 144 of the stake 138 may be positioned below the upper edge 142 of the member 140 much in the same manner as the top of the stake is positioned in concrete form 20 as shown in FIGURE 1 and such positioning 7 may be preferred in certain applications.

The concrete form 146 shown in FIGURE 15 is similar in many respects to some of the other concrete forms described above. More specifically, concrete form 146 comprises a plurality of aligned stakes 148 (only one of which is shown in FIGURE 15) and a joint forming member 150. Each of the stakes 148 has a plurality of apertures 152 formed therein. It will be understood that a plurality of appropriately formed recesses could be used in lieu of the apertures 152. The joint forming member is securely mounted relative to the stakes 148 through the use of a special crimping tool 154, shown in FIGURE 16, comprising a pair of pivotally mounted jaw members 156 and 158. One of the jaw members, member 156, has a boss portion 160 extending generally at right angles thereto. The other jaw member 158 has one or more boss members 162 and 164 also formed at right angles thereto. The boss members 162 and 164 are preferably conically shaped while the boss member 160 is preferably cylindrically shaped. Boss member 162 is preferably formed longer than was member 164. The purpose for this is to decrease the amount of crimping force required. Jaw member 158 also includes a second boss member 166 which limits the pivotal movement of jaw member 158 toward jaw member 156 thereby insuring that the portion of the joint forming member 150 disposed between the jaw members is not affected by the crimping action of the tool 154.

FIGURE 17 shows another embodiment of a concrete form 168 constructed in accordance with the subject invention. The concrete form 168 comprises a plurality of aligned stakes 170 (only one of which is shown in FIG- URE 17) and an elongated relatively rigid sheet material member 172. Each of the stakes 170 has a support means 172 disposed generally transversely to the remaining portion of said stake 170 and one or more apertures formed within said stake (not specifically shown). The member 172 is similar to member 28 as shown in FIGURE 2 except that the means or aperture 174 has a greater vertical depth than the means 36 shown in member 28, the folded-over portion 176 has a longitudinally extending means 178 formed therein which is shown as a corrugation and which has for its purpose to increase the overall rigidity of the folded-over portion 176, and the member 172 has been suitably deformed such as with a crimping device similar to that shown in FIGURE 16 whereby portions 180 of said member 172 are disposed within the apertures formed within the stake 170. As shown, the support means or tab 172 has been bent downwardly for the purpose of better securing the member 172 relative to the stake 170. The member 172 also differs from the member 28 as shown in FIGURE 2 in that member 172 is formed without the plurality of groups 52 of apertures 54 as is the case with member 28 as shown in FIGURE 2. It will be readily appreciated that deforming member 172 by urging portions 180 within the apertures or, if desired, appropriately formed recesses within the stake 170 precludes the necessity of incorporating groups of apertures within the lower planar portion of member 172.

Referring now to FIGURES 15, the installation of the concrete form 20 as shown in FIGURE 1 is now described. After the subgrade or sub base 62 has been formed and suitable side forming (not shown) has been installed, a string or line (not shown) is extended from one side of the sub base 62 :to the other side thereof at a predetermined grade level, preferably the grade level represented by the dotted line 3 4. Next, a section or sections of joint forming members 2 8 are laid adjacent the line established by said string. The purpose for this is to facilitate the spacing of the stakes along the line established by such string. However, it will be appreciated that the spacing may be determined in any of several other ways since the spacing between the means 36 of member 38 will admit some variation in installation thereby precluding an exact, precise spacing of the stakes. For example, where a two-foot spacing interval is desired or required,the length of the means 66 is made sufficiently long to permit center to center spacing between the means 36 to vary up to approximately 4 or 5 inches. \After the unember or members 28, depending on the width of the concrete slabs, are positioned upon the subgrade 62 as described, the blocks 60 are secured to the stakes -26 and then the stakes are installed one at a time along the line established by the string at the desired spacing interval. As previously indicated, the blocks 60 need not be used where the subgrade is firmly compacted. Each stake 26 is driven into the subgrade 62 until a predetermined portion of the support means 32, such as the upper surface thereof, is disposed along a predetermined grade level, preferably the grade level as represented by the dotted line 34. Next, each of the members '28 is mounted upon the stake 26 by positioning the member 28 until each of the support means 32 extends through the means 36. It will be understood that the height of the means 36 will exceed the height or depth of the support means 32 by a suflicient amount to permit member 28 to be mounted easily and quickly upon the stake "26. After the member or members 28 have been installed upon the stakes 26 as described, it *will be readily appreciated that the upper edge 47 of the upper planar portion 68 and the foldedover portion 45 will be disposed along a predetermined grade level such as the grade level represented by line 50, said line 50 normally coinciding with the upper surface of the concrete slabs 22 and 24. Thus, said upper edge 47 will serve and function as a screed lrey to facililtate the leveling of the freshly poured concrete to a predetermined grade level. It will be understood that the support means or tabs 32 maybe bent upwardly or downwardly following the installation of member '28 upon the stakes 2-6. If desired or required, a dowel or rod 59 may be installed within each dowel aperture 58. Additionally, the screw 56 may be installed within one of the apertures 33 and caused to extend through a corresponding aperture 54 formed in the lower planar portion 40 of the member 28. After the foregoing has been accomplished, the concrete form 20 is ready tor the pouring of concrete. The concrete is poured on the subgrade 62 to form first a concrete slab 24. More specifically, the concrete slab which is poured first is that which is adjacent the convex portion of the member 28. In FIGURE 1, the first concrete slab poured is slab 24. The concrete may then be poured on the subgrade 62 to form the slab 22. After the pouring of the concrete to form the slabs 24 and 22, the upper surface of said slabs may be suitably leveled or smoothed by means of a rod or leveling member which may be supported, at least in part, during its back and forth movement on the upper straight edge 47 of the member 28. Thus, the upper straight edge 47 of member 28 functions as a screed.

Referring now to the concrete form 63 shown in FIG- URE 6, the stakes 64 are installed in the same manner as described above in connection with the concrete form 20 shown in FIGURE 1. iFollowing installation of the stakes 64, the member 66 is mounted upon the stakes by positioning the member 66 at a predetermined height in order to permit the support means 68 to pass through the aperture formed in the upper planar portion of the member 66. Thereafter, the first support means 68 is bent downwardly and the second support means 70 is c-rimped or bent toward the remaining portion of the post 64 (thereby securing the lower planar portion of the member 66 to the stake 64 to prevent vertical movement thereof rel-aiIlVC to said stake.

Referring to FIGURES 8 and 9, the stakes of the concrete form 78 are installed in the same manner as the stakes '26 of the concrete form 20 shown in FIGURE 1. Subsequently, the member 82 is positioned relative to the stake '80 whereby the support means 84 is disposed within the recess 92. -It will be appreciated that the longitudinal spacing of the stakes 80 may vary more in the concrete form shown in FIGURE 8 without adversely affecting the installation of the member 82 thereupon. However, it will also be appreciated that due to the structural characteristics of the concrete form 78, the longitudinal spacing of the stakes 89 must be maintained within certain predetermined limits it the concrete form 78 is to function as designed. After the member 82 has been installed as described, it is preferable to use a screw 88 installed within one of the plurality of apertures 86 formed within the stake 80 and which also extends through a corresponding aperture formed in the lower planar portion 104 of member 82 to secure member 82 against vertical movement relative to the stake 80. It will be understood that means other than a screw 88 may be used to elfect the same purpose; for example, in referring to FIGURE 2, a wire may be passed through one of the apertures formed in the stake and a corresponding aper- 9 ture formed in the member mounted upon the stake and thence back again through another one of the apertures formed in said member. The ends of the wire may then be intertwined or otherwise secured to each other for the purpose :of maintaining the member '82 in a predetermined vertical position.

Referring to the concrete form 106 shown in FIGURE 11, again the stakes 108 are installed in accordance with the precedure outlined above with respect to the concrete form 20 shown :in FIGURE 1. Thereafter, the member 110 is mounted relative to the stakes 108 such that the support means 1112 are disposed within the horizontally disposed recess 12 2. Subsequently, the second support means 114 may be crimped or bent toward the remaining portion of the post 108 for the purpose of securing the lower planar portion 118 to the stake 108.

Referring to the concrete form shown in FIGURE 13, again the stakes 133 are installed in the same manner as described above with respect to the stakes 26 shown in FIGURE 1. Thereafter, the member is mounted in the same manner as member 110 described above with respect to FIGURE 11. However, it will be appreciated that the stake 133 need not use a second support means similar to second support means 114 of stake 108 shown in FIGURE 11 nor will a separate means such as the screw 88 shown in FIGURE 8 be required to maintain the member in a predetermined vertical position since this is accomplished directly by the recess portion 128 and the support means 132.

Referring to the concrete form 136 shown in FIGURE 14, the stakes 148 are installed in accordance with the procedure outlined above with respect to stakes 26 shown in FIGURE 1. Thereafter, the joint forming member is mounted upon the stakes 138 in much the same manner as the joint forming member 28 FIGURE 2 is mounted upon stake 26 as shown in FIGURE 1. It will be understood that stake 138 may be formed either similar to the stake 26 shown in FIGURES 1 and 3-5 or the stake 64 shown in FIGURES 6 and 7. Further, the lower planar portion (not shown) of the joint forming member shown in FIGURE 14 may be formed either with or without the plurality of groups of apertures as is the case with the joint forming member 28 shown in FIGURE 2. It is to be understood, of course, that the top 144 of the stake 138 will be disposed either at the same level of the upper surface of the concrete slab to be formed or slightly below such level.

Referring to EIG URES and 16, the stakes 148 are mounted in much the same manner as the stakes 26 of the concrete form shown in FIGURE 1. It will be understood, however, that the top of the stakes 148 need not be positioned with the same degree of accuracy as the top of the stakes 26 as shown in FIGURE 1. For example, the tops of the stakes 148 may be vertically positioned to an approximate grade of elevation which may vary by as much as /2 to 1 inch. Thereafter, a predetermined grade elevation (not shown) is marked on each of the stakes through the use of a chalk line. This predetermined grade elevation may be taken with respect to any predetermined portion of the joint forming member 150. In other words, the grade elevation as marked upon each of the stakes will be a predetermined distance below the upper surface of the concrete slabs which are to be formed. Following this, the crimping tool 154 is mounted with the boss portion 160 of jaw member 156 disposed within one of the apertures 152 formed in the stake 148. The joint forming member is then positioned with a portion thereof disposed along said predetermined grade elevation. Then, the jaw member 158 is pivoted toward jaw member 156 thereby forcing the boss portions 162 and 164 of jaw member 158 into adjacent portions of the joint forming member 150 thereby causing said adjacent portions of joint forming member 150 to be disposed within the remaining apertures 152 formed within stake 148. Upon pivoting jaw member 158 away from jaw member 156 the crimping tool 154 10 is easily and quickly removed from the stake 148. As a. result of this crimping action, the joint forming member is securely mounted relative to the stake 148 in such a manner that there is no vertical movement of the joint forming member 150 relative to the stake 150.

Referring to FIGURE 17, the stakes are mounted in much the same manner as the stakes 148 described in connection with concrete form 146 shown in FIGURE 15 with the only exception that the top of the stakes 170 must be set to a vertical elevation within a tolerance as limited by the vertical height of the aperture or opening 174 formed within joint forming member 172. in other words, if the vertical height of opening 174 is /2 inch, the top of each stake 170 must be set within one-half inch of a predetermined grade elevation. The use of the joint forming member 172 shown in FIGURE 17 is believed to be slightly advantageous over the use of the joint forming member 150 shown in FIGURE 15 since the entire member 172 will be supported upon each of the stakes 170 prior to the crimping of any portions of member 172 into apertures or recesses formed in one of the stakes 170. Thus, it is somewhat easier for a person in the ifield to install a joint forming member 172 on stake 170' than to install a joint forming member 150 on stake 148. Although the joint forming member 172 preferably has portions thereof crimped relative to each stake 170, it is to be understood that such is not mandatory and that such crimping action may be limited to a number of stakes less than all such stakes used to support said joint forming member 172. It has been found that the use of the folded-over portion 176 containing the means 178 is preferred since means 178 increases the overall rigidity of the folded-over portion and the upper part of the upper planar portion as well. Such increased rigidity effects a straighter upper edge than would otherwise be the case.

Although several embodiments of the herein invention have been shown and described, at the present time the concrete form 168 with its joint forming member 172, as shown in FIGURE 17, is the preferred concrete form and joint forming member of this invention while the concrete form 20 and the joint forming member 28 shown, respectively, in FIGURES 1 and 2 is the next preferred form and joint forming member of this invention.

In view of the foregoing, it will now be readily apparent that a vastly improved concrete form and member useful therein has been described. For example, it will be readily appreciated that a concrete form has been described which may be quickly and easily installed in the field by a single individual and that same may be used for monolithically poured concrete slabs without resort to checker board pouring. Further, concrete forms constructed in accordance with the subject invention may be used for relatively thick concrete slabs, i.e., 8 inches or more, without experiencing detrimental spalling or breaking thereof adjacent the upper surfaces of the concrete form. Additionally, concrete forms constructed in accordance with the subject invention provide a number of means for easily, quickly and inexpensively securing the joint forming member thereof against vertical movement relative to the supporting stakes thereby assuring that the upper edge of such member is properly positioned to function as a screed. -Also, concrete forms constructed in accordance with the subject invention may be used in conjunction with concrete slabs which are subjected to relatively heavy loading and beneficial results obtained for both relatively thick concrete slabs and relatively thin concrete slabs.

It is to be understood that this invention is not limited to the exact embodiments of the concrete forms and joint forming members shown, which are merely by way of illustration and not limitation, as various other forms and modifications will be apparent to those skilled in the art, and it is therefore intended that the appended claims cover all such changes and modifications.

I claim:

1. A concrete form of the type used in forming a key contraction joint between concrete slabs, said joint comprising:

a plurality of spaced apart aligned stakes, each of said stakes having a generally vertically disposed body portion, a top, and a tab portion formed adjacent said top and below thereof, said tab portion being disposed generally transversely to said body portion, said stakes adapted to be driven to predetermined heights so that the tops of said stakes are disposed along a predetermined grade level; and

an elongated relatively rigid sheet material member having upper and lower longitudinally extending generally co-planar portions, and a middle, longitudinally extending key deformation portion connecting said upper and lower planar portions, a plurality of longitudinally spaced apart apertures formed in said elongated relatively rigid sheet material member, the longitudinal spacing of said apertures corresponding to the longitudinal spacing of said stakes, each of said apertures having a tab portion from a corresponding stake extending therethrough to support said sheet material member so that the upper edge of said upper planar portion is disposed along a predetermined grade level, the end of said tab portions being bent to secure said elongated relatively rigid sheet material member with respect to said stakes to prevent vertical movement thereof.

2. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 1 wherein said apertures are formed in the lower part of said upper planar portion.

3. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 1 including fastening means for fastening said lower planar portion to said stakes.

4. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 3 wherein the upper edge of said upper planar portion is folded toward said plurality of stakes to form a further planar portion lying between said upper planar portion and said stakes.

5. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 4 including a longitudinally extending corrugation located in said upper planar portion beneath said plurality of apertures.

6. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 5 including dowel apertures formed in said longitudinally extending key deformation portion.

7. A concrete form of the type used in forming a key contraction joint between concrete slabs, said joint comprising:

a plurality of spaced apart aligned stakes, each of said stakes having a generally vertically disposed body portion, a top, and a tab portion formed adjacent said top and below thereof, said tab portion being disposed generally transversely to said body portion, said stakes adapted to be driven to predetermined heights so that the tops of said stakes are disposed along a predetermined grade level; and

an elongated relatively rigid sheet material member having upper and lower longitudinally extending generally co-planar portions and a middle, longitudinally extending key deformation portion connecting said upper and lower planar portions, said upper planar portion having an upper edge and a longitudinal recess extending parallel to said middle portion formed therein, said. recess having the tab portions of said stakes extending therein to support said sheet material member so that the upper edge of said upper planar portion is disposed along a predetermined grade level, said recess being crimped at the locations of said tab portions to secure said elongated relatively rigid sheet material member with respect to said stakes to prevent vertical movement thereof.

8. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 7 including fastening means for fastening said lower planar portion to said stakes.

9. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 7 wherein said fastening means comprises tabs located on said stakes adjacent the lower edge of said lower planar portion, said tabs bent upwardly to hold said lower planar portion with respect to said stakes to prevent downward movement thereof.

10. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 9 wherein the upper edge of said upper planar portion is folded toward said plurality of stakes to form a further planar portion lying between said upper planar portion and said stakes.

11. A concrete form of the type used in forming a key contraction joint between concrete slabs as claimed in claim 10 including dowel apertures formed in said longitudinally extending key deformation portion.

12. A concrete form of the type used in forming a key contraction joint between concrete slabs, said joint comprising:

a plurality of spaced apart aligned stakes, each of said stakes having a generally vertically disposed body portion, a stop, and a tab portion formed adjacent said top and below thereof, said tab portion being disposed generally transversely to said body portion, said stakes adapted to be driven to predetermined heights so that the tops of said stakes are disposed along a predetermined grade level;

an elongated relatively rigid sheet material member having upper and lower longitudinally extending generally co-planar portions, and a middle longitudinally extending key deformation portion connecting said upper and lower planar portions, a plurality of longitudinally spaced apart apertures formed in said elongated relatively rigid sheet material, the longitudinal spacing of said apertures corresponding to the longitudinal spacing of said stakes, each of said apertures having a tab portion from a corresponding stake extending therethrough to support said sheet material member so that the upper edge of said upper planar portion is disposed along a predetermined grade level; and

fastening means for fastening said lower planar portion of said elongated relatively rigid sheet material member to said plurality of stakes, said tab portions, said apertures and said fastening means cooperating to prevent vertical movement of said sheet material member relative to said stakes.

13. A concrete form of the type used in forming a key contraction joint between concrete slabs, said joint comprising:

a plurality of spaced apart aligned stakes, each of said. stakes having a generally vertically disposed body portion, a top, and a tab portion formed adjacent said top and below thereof, said tab portion being disposed generally transversely to said body portion, said stakes adapted to be driven to predetermined heights so that the tops of said stakes are disposed along a predetermined grade level;

an elongated relatively rigid sheet material member having upper and lower longitudinally extending generally co-planar portions and a middle, longitudinally extending key deformation portion connecting said upper and lower planar portions, said upper planar portion having an upper edge and a longitudinal recess extending parallel to said middle 13 portion formed therein, said recess having the tab portions of said stakes extending therein to support said sheet material member so that the upper edge of said upper planar portion is disposed along a predetermined grade level; and

member relative to said stakes.

a plurality of spaced apart aligned stakes, each of said stakes having a generally vertically disposed body portion, a top, and a tab portion formed adjacent said top and below thereof, said tab portion being disposed generally transversely to said body portion,

fastening means for fastening said lower planar portion said stakes adapted to be driven to predetermined of said elongated relatively rigid sheet material memheights so that the tops of said stakes are disposed ber to said plurality of stakes, said tab portions, alongapredetermined grade level; and said recess and said fastening means cooperating to an elongated relatively rigid sheet material member prevent vertical movement of said sheet material having upper and lower longitudinally extending generally co-planar portions and a middle, longi- 14. A concrete form of the type used in forming a key contraction joint between concrete slabs, said joint comprising:

a plurality of spaced apart aligned stakes, each of 15 tudinally extending key deformation portion connecting said upper and lower planar portions, said upper planar portion having an upper edge and a longitudinal recess extending parallel to said middle said stakes having a generally vertically disposed body portion, a top, and a tab portion formed adjacent said top and below thereof, said tab portion being disposed generally transversely to said body portion formed therein, said recess having the tab portions of said stakes extending therein to support said sheet material member so that the upper edge of said upper planar portion is disposed along a portion, said stakes adapted to be driven to predetermined heights so that the tops of said stakes are disposed along a predetermined grade level; and

an elongated relatively rigid sheet material member having upper and lower longitudinally extending predetermined grade level.

References Cited UNITED STATES PATENTS generally co-planar portions, and a middle, longi- 1349340 8/1920 Hotchklss' tudinally extending key deformation portion con- 1,770,359 7/ 1930 Fischer necting said upper and lower planar portions, a 2,332,109 10/1943 Parmenter 94-17 plurality of longitudinally spaced apart apertures 2848 929 8/1958 Wilbur 9 7 formed in said elongated relatively rigid sheet material member, the longitudinal spacing of said aper- 3O57269 10/1962 Amgalas et a1 94 17 tures corresponding to the longitudinal spacing of 3,143,783 8/1964 Gaetke said stakes, each of said apertures having a tab 3,288,042 11/1966 Gaetke 9451 portion from a corresponding stake extending there- 3,357,324 12/ 1967 Tone et al 94-51 XR through to support said sheet material member so that the upper edge of said upper planar portion JACOB L. NACKENOFF, Primary Examiner. is disposed along a predetermined grade level. 15. A concrete form of the type used in forming a key contraction joint between concrete slabs, said joint comprising:

U.S. Cl. X.R. 94-51 

